Exporting STL files from SOLIDWORKS for 3D Printing

Correctly converting CAD files into STL files is very important in order to print accurate parts. An STL file is a triangulated approximation of a 3D CAD model. The amount of triangulation in the STL file will effect how faceted the surface of the part appears once printed. Too few triangles, and a circle becomes a stop sign. The level of triangulation, and effectively the amount of faceting, can be controlled during the CAD export to STL. Just as it is possible to have too FEW triangles define your part, you can also overshoot and have too MANY triangles which creates a large file, and a level of detail that the printers can't achieve anyways.

Today we will be talking about how to adjust the settings in SOLIDWORKS to achieve a good STL file for 3D printing.


In SOLIDWORKS, simply go to File > Save As.



In the Save As window, choose STL as file type. This will unlock an "Options" button that will allow you to manually adjust the export settings.



Clicking the Options button will bring up the following window. For best results, output as Binary, and set Resolution to "Fine". These settings will suffice for most parts, but in some cases, it will be necessary to use a Custom Resolution to increase the number of triangles used.



The following Custom Resolution settings are what was used for the red "Custom" sphere shown below.



A good rule of thumb to determine whether or not your resolution is high enough is to try and count the triangles on your part. If you can easily count the number of facets across your part, you need to increase resolution, and if you can't see any faceting at all, and your file size is very large (20+MB) you may need to decrease resolution. In the example below, the Fine setting is going to print well, even though you can still see some slight faceting. The Fine setting gives us the best mix of resolution and file size. On more complex parts, the Custom settings can quickly increase the file size of a part, causing the 3D printing software to get bogged down in calculations.




Owen Lu | Application Engineer

Computer Aided Technology

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